She was spared a prison sentence, but Rivlin said that this was due to her own ill health and the fact she has two adult disabled children.

"You could easily have afforded to pay her a reasonable sum by way of wages," said judge Geoffrey Rivlin during sentencing at London's Southwark Crown Court.

"You chose to give her virtually nothing.

"Your own behaviour was callous and greedy," the judge added.

Mruke was initially paid 10 pounds per week, but this allowance was stopped within a year.

Khan, who was found guilty of trafficking a person into the UK for exploitation, forbade Mruke from leaving the house in Harrow, north west London, and fed her two slices of bread a day.

The court had heard how Mruke was brought to Britain after working at a hospital in Dar Es Salaam in Tanzania, which Khan owned.

Khan promised to pay Mruke 50 pounds a week and said she would only have to work six hours a day.

"I felt like a fool, I was treated like a slave," Mruke, who was saving up to help her daughter through college, said.

"I was hoping I would receive a salary and improve my life. But my hopes were dashed, my strength was reduced and I became unwell."

Rivlin said Khan had told a "pack of lies" during the trial and had taken advantage of her "naive and illiterate" victim.

Mruke told the court that she would wake up at 0600 GMT and then clean, garden, cook and go for walks with Khan's sons before finally being allowed to sleep on a mattress in the kitchen at around midnight.

"I feel that justice should be passed and others should learn from this. I feel terrible about her," Mruke said.

Mruke's plight only came to light when she was allowed to visit a doctor over her varicose veins.

Mruke's parents both died during her three-year ordeal, but she was allowed no contact with her family in Tanzania.

Earlier, prosecutor Caroline Haughey told Southwark Crown Court: "From the moment of her arrival in England Mwanamisi was made to sleep, work and live in conditions that fall by any understanding into that of slavery."